Welding electrodes consist of a very hard material such as tungsten with high stability even at high temperatures. There are welding electrodes with different cross sections. The welding electrodes have a tip or an edge at its end. The form of the welding electrodes depends on their respective application. Such tips suffer from wear during operation.
Welding electrodes can be bought with pre-manufactured tips. The tip is worn after its use. The welding electrodes are then discarded. This is expensive because high-quality material is expensive.
It is known to regrind used welding electrodes. This is usually carried out manually on open grinding- or cutting-off wheels. This method is inaccurate and dangerous. Furthermore devices are known with an open grinding wheel wherein the welding electrodes are guided at a certain angle with respect to the grinding wheel by a guiding sleeve. Such devices are also expensive. It is especially expensive to adapt the device to match the various types of welding electrodes or the various shapes of the tips or cutting edges. This requires the exchange of the guiding sleeves.
A device for producing electrodes with a plurality (for example 6) of different electrode cross sections with a plurality of different tip angles (for example 4) and a plurality of lengths is a useful and cost-saving means.
From the DE 100 10 520 A1 a device for processing welding electrodes with a grinding wheel is known. The grinding wheel rotates within a grinding wheel housing. The device also has a housing cap fixed to the grinding wheel housing and having at least one lateral opening for guiding a welding electrode for processing into a defined position relative to the grinding wheel. The plane of the grinding wheel is essentially the separating plane between the grinding wheel housing and the cap. The cap can have a plurality of different lateral openings spaced apart for receiving different types of welding electrodes. The cap can also have a plurality of lateral openings spaced apart with axes crossing the plane of the grinding wheel at different angles. A radial slit can be formed in the grinding wheel housing extending over the front surface of the housing. A welding electrode can be guided through the slit for cutting at the lateral surface of the grinding wheel. In the disclosed device the grinding wheel is fixed to a grinding wheel seat which is connected to the shaft of the driving motor. The entire device is a portable unit.
The device known from the prior art allows the grinding of thick electrodes as well as thin electrodes. It is, however, a disadvantage that the grinding wheel which is required to achieve a fine grinding result has only a small grinding rate. This is particularly disadvantageous with thick electrodes. Therefore, each time, when a high grinding rate is necessary the fine grinding wheel has to be replaced by a rougher grinding wheel. This is time consuming.
US 2004/0127149 A1 to the applicant discloses an assembly, where two parallel grinding wheels with different graining are used. A first grinding wheel runs in a cavity between the motor flange and a first housing. The second grinding wheel runs in a second hollow space between the first housing and a second housing. The housings are provided with openings for guiding the welding electrodes. The known assembly allows the use of different grinding wheels without dismounting and re-assembling.
Thus, one object of the invention is to provide a less expensive assembly of the above mentioned kind with smaller diameters.